Many computer programs exist in which an operator is presented with a list of items from which to choose one or multiple ones of the items for an action to be performed thereon. Such programs have become popular because human factors studies have shown that it is easier for users to recognize and select desired items from a list on the display screen, rather than having to remember the items (or make reference to another list) and type them. For example, consider the many programs available for maintaining the organization of program and data files on the hard disk of a personal computer. Such programs exist which allow an operator to mark one or more files to be, for example, copied, erased, or moved to another directory, disk or diskette. Alternatively, instead of choosing one or more files on which an action is to be taken, the operator may be presented with a list of actions to be performed on one or more files.
It is a common practice to allow an operator to select a desired choice in a list of choices by moving a highlight bar to the choice (with the aid of cursor direction keys or a pointing device such as a mouse) and pressing a keyboard key or mouse button to enter the choice. In programs in which only one choice at a time may be made, the selected choice may be submitted immediately to the system for processing, since no other choices are allowed. In programs in which a plurality of choices are allowed before processing of the choices takes place, the first selection cannot be immediately submitted because the user may need to make additional selections before submitting the field.
Accordingly, these two types of selection fields--the single choice field and multiple choice fields--have been mutually exclusive. While it is immediately obvious that multiple choices are not allowed when only a single choice is permitted, it must also be understood that where multiple choices are permitted, systems have been unable to recognize a single choice as being the only choice intended, since additional choices were allowed.
The single choice selection field provides better ease-of-use characteristics, because the choice is submitted to the system for processing just as soon as the choice is made. The operator does not sit and wonder if other necessary actions have been completed, because processing with the single choice can be undertaken as soon as the choice has been made, since only one choice is allowed. There are many applications in which selection of one choice at a time will be most typical, with only a occasional need for the selection of multiple choices. For example, consider a list of file names wherein the operator can select the name of a file and an action to be performed on it, such as "Erase". The typical situation will require erasing a single file. However there are also situations in which it is desirable to select several file names and request "Erase" for all of the files at once. The novice and casual users need the benefits of single choice field characteristics, while the more experienced user desires the capabilities of multiple choice fields.
As an example the IBM DisplayWrite 1 program allows a directory of files to be listed. The user may pick one of several choices of actions to be performed on a single file. Assume then that the user chooses "Erase" and moves the movable bar up or down the list of files and stops this movable bar on a file intended to be erased. When the Enter key is depressed the action to erase this chosen file begins. As another example consider a file manager program in which multiple files may be chosen for erasure. If the operator depresses the Enter key after choosing only one file (following the procedure of the DisplayWrite 1 program) the erasure process does not begin. Instead, the operator is prompted to use the space bar to select the files to be erased and then to depress the Enter key at the completion of selecting all of the choices. The operator is, therefore, not allowed to use the intuitively obvious technique of processing the single choice as is employed in the program which allows only single choices.
It would, therefore be of great benefit and utility to provide the ability within one program or system to make multiple choice selections while simultaneously allowing a single choice to be as immediately processed as in programs or systems which allow only single selections.